date: fix the strftime O and E modifier leaks #11656 (new)

[tobyw21]

This is a new PR to a broken old PR #11714 and trying to address issue #11656.
This PR fixes date: strftime with O and E modifiers. Fixes #11656

Changes

• coreutils/src/uu/date/src/format_modifiers.rs:105, in bytes matching, added O and E bytes match.
• add tests for O and E modifiers with valid specifier and invalid specifiers according gnu date behaviours in the documentation

Limitations

Currently block the BrokenDownTime calling to_string_with_config if modifier E or O combines with invalid specifiers. It pre-checks if modifier is O or E, then skip formatting if modifier is E and specifier is not in '%c', '%C', '%x', '%X', '%y' and '%Y', or if modifier is O and specifier is in '%a', '%A', '%c', '%D', '%F', '%x' and '%X'. While Jiff does not support modifier E and O, this check is to be done outside of Jiff.

Build requirements

Rust stable

Testing

Tested with make test

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/pr/bounded-memory (passes in this run but fails in the 'main' branch)
Congrats! The gnu test tests/tail/retry is no longer failing!
Congrats! The gnu test tests/expand/bounded-memory is now passing!